The invention relates to a multipoint injector intended to be mounted in an injection system fixed to a combustion chamber housing of a turbomachine, such as an aircraft engine. It relates more particularly to the structure of such an injector and, in particular, the part of the structure dedicated to supplying the pilot circuit and multipoint circuit and to the cooling thereof.
Fuel injectors known as “multipoint” fuel injectors are a new generation of injectors which make it possible to adapt to different speeds of the turbomachine. Each injector is provided with two fuel circuits: that known as the “pilot” circuit which has a continuous flow optimized for low speeds and that known as the “multipoint” circuit which has an intermittent flow optimized for high speeds. The multipoint circuit is used when it is necessary to have additional thrust from the engine, in particular in the cruising and take-off phases of the aircraft.
At raised temperatures, the intermittent operation of the multipoint circuit has the major drawback of causing decomposition, otherwise known as coking, of the fuel stagnating inside the multipoint circuit when the flow thereof is considerably reduced, or even cut off. To eliminate this risk of coking, it is known to use the fuel circulating in the pilot circuit as cooling fluid for the fuel stagnating in the multipoint circuit.
Unfortunately, until now, the structure of the existing multipoint injectors has been such that the two pilot and multipoint circuits overlap one another. More specifically, such overlapping does not allow the cooling to be achieved in a satisfactorily uniform manner.